In order to analyze their performance in a quantifiable manner, athletes will often measure various performance information. One class of performance information includes time parameters corresponding to an athlete's travel over a distance. For example, a runner may measure the total elapsed time required to run a distance, the elapsed time required to run a segment of a distance, and/or the average time required to run equal segments of a distance. Another class of performance information relates to the athlete's own physical parameters. Thus, an athlete may measure his or her heart rate, body temperature, blood pressure, or volumetric expansion of his or her lungs while performing an activity like running or biking. In many situations, and particularly with regard to measuring the total elapsed time required to run a distance or the elapsed time required to run a segment of a distance (e.g., a “lap” time or a “split” time), an athlete will use a watch to measure the desired performance information.
Accordingly, some conventional watches for athletic use may have a variety of different operational modes for measuring and displaying different types of information, including performance information. For example, a watch may have a time or chronometer mode for displaying the current time in the user's time zone (and, with some watches, the current time in one or more other time zones). The same watch may also have a performance mode (sometimes referred to as a “sport” mode or “run” mode) in which the watch's primary operation is measuring and/or displaying performance information. For example, in the performance mode, a watch may execute a chronographic function for measuring both a total elapsed time and individual segments of a total elapsed time (each segment of the total elapsed time being, for example, the amount of time required to travel a segment of a total distance). Still further, if the watch operates in conjunction with a sensor, such as a speed/distance monitor, heart rate monitor, blood-oxygen content monitor or the like, then the watch may receive and display performance information from a sensor or sensors in the performance mode. A watch also may have, e.g., an alarm mode for activating and scheduling an alarm. It may also have a data mode for accessing and displaying stored measured athletic information, such as previously recorded lap times.
Typically, however, a conventional watch will not modify the operation of its user interface to accommodate some of the special circumstances involved when a user is employing the watch to measure or display his or her athletic performance. For example, while many watches provide a light button for illuminating the watch's display, this button may be very difficult for a user to simultaneously depress with another button that may need to be activated to view a desired athletic performance measurement. For example, if a user operating a conventional watch at night wishes to view the time that elapsed while he or she ran a distance or a segment of a distance, then the user must simultaneously depress both a “light” button and a “start/lap” button. Even if the user can accomplish this simultaneous button activation while running, the light may not remain on long enough for the user to view all of the information displayed by the watch (e.g., in response to the activation of a “lap” button, some watches will display both a total elapsed time and the most recently measured lap time or split time).
Also, the watch may be configured to blindly measure an athletic performance value that is unrealistic or even impossible. For example, a user may employ a conventional watch to measure the time that elapsed while he or she ran a segment of a distance (i.e., a “lap” time or a “split” time) while continuing to measure a total elapsed time required to travel the total distance. If the user inadvertently depresses the “start/lap” button (while, for example, attempting to simultaneously depress a “light” button), then the watch will automatically record and display the lap time or split time when the button is depressed, even if that lap time is too low for the user to have run a distance segment of any significant length.